Local and post-local buckling behavior of welded steel shapes in partially encased composite columns

Abstract

This paper presents a theoretical study on both local and post-local buckling behaviors of partially encased composite (PEC) columns, made with thin-walled, welded H-shapes and concrete encasement between flanges; transverse links are welded between flange tips to reinforce the section. Nonlinear finite element analysis (FEA) was conducted to predict buckling behaviors and strengths of steel shapes. Finite element models were verified through a comparison of FEA results with experimental results. A parametric study was then performed using validated FEA models to investigate the effect of several parameters on the buckling behavior of PEC columns. The residual stress of steel shapes, which is introduced through welding process, was discussed in detail. Based on the parametric study, a series of expressions was developed for predicting critical strength, post-buckling strength, as well as the entire stress-strain relationship of steel shapes in PEC columns under concentric loading.